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assemblyx86masm

I am doing the sum of an array of elements in x86 assembly language. I should be getting 100000 in the ecx register but i am getting A0000?

so i have a variable of type DWORD: var2 DWORD 10000h,20000h,30000h,40000h

and my program is:

.data
var2 DWORD 10000h,20000h,30000h,40000h

.code
main PROC

mov eax, 0
mov ebx, 0
mov ecx, 0
mov edx, 0
mov eax, [var2]
mov ebx, [var2+4]
mov ecx, [var2+8]
mov edx, [var2+12]
add eax,ebx
add ecx, edx
add ecx, eax



call DumpRegs

exit

main ENDP
END main

Everything seems to work fine and my registers look like registers output

But the actual answer should be 100000h shouldn't it be? as 10000 + 20000 + 30000 + 40000 is 100000h.

I have tried changing the registers, putting the total in a variable and then moving it to a register but I keep getting the same A0000.

Solution

  • But the actual answer should be 100000h shouldn't it be? as 10000 + 20000 + 30000 + 40000 is 100000h.

    No, you are mistaken.

    10000h + 20000h + 30000h + 40000h = A0000h

    (To get 100000h, you'd have to add another 60000h at the end.)

    You can try this in any calculator that supports hexadecimal (for example Windows', if you change to programmer mode). It's also logical from the fact that 1 + 2 + 3 + 4 = 10 in decimal, and 10 in decimal is A in hexadecimal.

    00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10
|1>|--2->|---3--->|-----4---->^^